Process of lubricating photographic film



thus avoiding any extra steps. It is, there- 1T0 Drawing.

Patented (Oct. 25, 1932 UNITED STATES.

PATENT OFFHCE KENNETH C. D. HICKMAN, OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK PROCESS OF LUBRICATING IPHOTOGRAPHIC FILM This invention-relates to processes of lubricating photographic film. One object of the invention is to provide a simple, inexpensive and accurately controlled process for lubrieating such film. Another object is to provide a process which can be applied to the film while it is in the wet condition during the photographic fluid treatment prior to drying. Still another object is to provide 'a' process which will accomplish the necessary lubrication without impairing the color or transparency of the film. Other objects will hereinafter appear.

Since my invention finds its greatest present field of usefulness in the lubrication of motion picture film, I shall describe its application to that branch of the art, but it will e understood that it can be employed with other films which frictionally-- engage the parts of the apparatus in which they are used. When motion picture films have been.

.the colloid picture-layer. This is generally gelatinous and is always water-permeable. The trouble has been combated heretofore by lubricating the surface of the picture-layer after the latter is dry, such as by theapplication of wax. Besides the extra manipulation of the film Which this entails, special precautions have to be taken to either keep inexpensive wa the waxoutside of the picture areas of the film, or else polished uniformly over the whole film surface. So far as I am aware, there has hitherto been no process which is applicable tothe lubrication of the film while it is in the wet condition during processing,

fore, highly desirable to provide asimple and of lubricating the film, wlnlewet from its ordinary treatment, without any added complications, and without Application filed January 30,1928. Serial No. 250,651.

liquid, or it may be fully dissolved therein, or

there may be present both an emulsified and a dissolved lubricant in the water. While the treatment with an aqueous emulsion or solution of lubricant is preferably applied to the film when it is wet, nevertheless, it is effective as additional treatment on otherwise dried and completed film.

I shall now describe several forms of my invention by way of illustration, but it will be understood that the invention is not limited to the details thus given, except as indicated in the appended claims. Since the lubricants are preferably colorless and transparent when present in extremely attenuated form in the final product, lubricating waxes and oils have been found to be very effective when dispersed in the aqueous'vehicle. For example, paraffin wax, carnauba wax or beeswax may be emulsified in water with the aid of a small amount of an emulsifying agent, such as castile soap. The technique of preparing such emulsions by agitating the ingredients together, say. in colloid mills, is

fully understood by those skilled in the art and need not be elaborated here.

A typical wax emulsion formula is beeswax 10 parts by weight, borax 2 parts by weight, gelatin 1 part by weight and water 1000 parts by weight. The slightly alkaline borax in the presence of the beeswax acts as an emulsifying agent. The gelatin helps in the keeping properties of the emulsion, but

'may be omitted without afi'ecting its lubricating properties. This bath may be applied to the processed motion picture film, which is otherwiseready for drying, by diluting said bath. by adding 10,000 to 100,000 parts by weight of water, say 20,000 parts by wei ht, and passing said film through this as the filial liquid treatment for it. When the water is finally evaporated from the film during drying, there is left evenly distributed on the surface of the picture-layer, an exceedingly thin, transparent, colorless layer of wax, which is capable of lubricating the passage of the film through the projection apparatus and yet is so minute as not to scrape off and pile up in the gate.

Instead of diluting the beeswax emulsion described above, it may be used at full strength by pouring, spraying or otherwise impinging it upon the wet moving film, removing the excess by a squeegeeing operation and then drying the film with a residue of the emulsion on it. A convenient method of air squeegeeing or blowing an excess of liquid off of the film is disclosed in my British Patent No. 217 ,642, accepted June 17 1924 pneumatic a paratus for removing adherent liquids rom the surface of photographic films and the like. If desired, lubrication can be confined solely to the picture-layer. of the film, and not to the support surface, but the operation is simpler and just as effective, if the emulsion contacts with both faces of the film.

The lubricants which I prefer to emulsify may, for the purposes of this application, bev

termed oleaginous, including by this term oils as well as waxes. For example, a suitable lubricating emulsion may be prepared by agitating together refined corn oil 25 parts by weight, saponin 1 part by weight, Turkey red oil (sulfonated castor oil) 6 parts by weight and water 2000 parts by weight. This is'a suitable strength for spraying on the film, followed by an air squeegee and drying. Where the film is to be immersed in it, it may be diluted from 10 to 100 times.-

Still a different emulsion may be prepared by agitating together 60 parts by weight of a colorless neutral mineral lubricating oil, Turkey red oil 30 parts byweight, sodium caseinate 1 part by weight,-sodium hydroxid 2 parts by weightand water 20,000 parts by weight. At the strength given, this is very suitable as a bath through which the film is passed, say as the last liquid treatment before drying in one of the well known motion picture continuous processing machines.

Sometimes it is desirable to prepare a much more concentrated emulsion, especially if it is to be transported for any considerable distance. Thus, in 3000 parts by weight of water there are emulsified 600- parts of a clear viscous parafiinoil in the presence of 100 parts by weight of Turkey red oil, '10 parts by weight of sodium casemate and 1 part by weight of sodium hydroxid. The 01]. may be of the type customarily employed for internal medicinal use. This emulsion may be diluted about 30 times for spraymg on the film, andmuch more than that for use as a plain bath. If this concentratedemulsionisto e kept in a stable condition fora considerable period, swollen'gelatin may be added to it oil are dissolved in 1000 parts of water. ;In' order to insure a clear solution, a small amount of alkali can be employed, say.2 parts by weight of a strong ammonia solu- 'tion. This solution of Turkey red oil,at the strength given, serves 'as a suitable spray for application to the film just prior to air squeegeemg and drying. \Vhen aqueous solutions of Turkey red oil, preferably slightly alkaline, are used as baths for the film, the concentration of the oil is preferably between 1% and 10%. It then tends not only to lubricate the gelatinous picture-layer, but to plastify it, making it very flexible with diminished curling tendencies, even in dry at- I mosphere.

If the water used in processing the film and,f

therefore, present in it when treated by my preparations, is hard, there is danger of impairing the lubricating quality of the finished film by. the formation ofcalcium, etc. soaps from the calciumsalts in the water. These therefore, preferable to wash the films, prior to the application of my preparations, with water that has been properly softened-to reare sticky rather than lubricating. It is, i

move the troublesome ingredient. The film should be washed substantially free from acid before it receives my treatment, because: the acid from an acid fixing bath may locally coagulate the emulsion and produce visible grease spots on the film. If the picture-layer has been hardened by means of an alum bath,

minimized or avoided when the above described emulsions or solutions are employed at the strength suitable for application by means of a jet. While'my baths are'es'pecially effective with water-permeable gelatin layers, they may likewise be used with any of the other water-permeable photographic colloid layers, such as collodion, albumen, etc.

In the present application I have claimed generically the use of a lubricant carried in an aqueous vehicle, whether it be-emulsified or dissolved therein; and I have also claimed the use of the emulsion species. In my copending application of even date herewith entitled Process of treating photographic film and product thereof, I have claimed the use of the solution species.

Having thus described my inventi rm, what there may be a tendency to form visible, d e-11 .posits of aluminum soap. This is greatly I claim as new and desire to secure by Letters Patent is: I

1. In the lprocess of lubricating hotographic film aving a water-permeab e colloid picture layer, treating said layer with a lubricant carried by an aqueous liquid vehicle in which it is homogeneously distributed, and drying said layer while it retains some of said lubricant,

2. In the process of lubricating photographic film having a water-permeable colloid picture layer, treating said layer with a substantially colorless oleaginous lubricant carried by an aqueous liquid vehicle in which it is" homogeneously distributechand drying said layer while it retains enough of said lubricant to leave a tenuous, transparent residue thereof.

3. In the process of lubricating photographic film having a gelatinous picture layer, treating said layer with a lubrlcating oil emulsified in water, and drying said layer while it retains some of said lubricant.

4. In the process of lubricating photographic film having a water-permeable colloid picture layer, applying to said layer, 1 while wet, an alkaline aqueous emulsion of an ,oleaginous lubricant, removing part of the adhering emulsion from said layer, and drying the latter.

5. In the process of lubricatin photoaphic film having a water-permea le elatmous picture layer, impinging on said ayer an alkaline aqueous emulsion of an oleaginous lubricant, blowing off the excess of emulsion from said layer, and drying the latter to leave a trtansparent tenuous residue of said lubrican Signed at Rochester, New York, this 26 day of January, 1928.

KENNETH C. D. HIGKMAN. 

